8a1e97ee2e
local_irq_restore -> raw_local_irq_restore -> irq_restore_epilog -> smtc_ipi_replay -> smtc_ipi_dq -> spin_unlock_irqrestore -> _spin_unlock_irqrestore -> local_irq_restore The recursion does abort when there is no more IPI queued for a CPU, so this isn't usually fatal which is why we got away with this for so long until this was discovered by code inspection. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
127 lines
2.2 KiB
C
127 lines
2.2 KiB
C
/*
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* Definitions used in MIPS MT SMTC "Interprocessor Interrupt" code.
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*/
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#ifndef __ASM_SMTC_IPI_H
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#define __ASM_SMTC_IPI_H
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#include <linux/spinlock.h>
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//#define SMTC_IPI_DEBUG
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#ifdef SMTC_IPI_DEBUG
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#include <asm/mipsregs.h>
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#include <asm/mipsmtregs.h>
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#endif /* SMTC_IPI_DEBUG */
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/*
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* An IPI "message"
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*/
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struct smtc_ipi {
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struct smtc_ipi *flink;
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int type;
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void *arg;
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int dest;
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#ifdef SMTC_IPI_DEBUG
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int sender;
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long stamp;
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#endif /* SMTC_IPI_DEBUG */
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};
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/*
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* Defined IPI Types
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*/
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#define LINUX_SMP_IPI 1
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#define SMTC_CLOCK_TICK 2
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/*
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* A queue of IPI messages
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*/
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struct smtc_ipi_q {
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struct smtc_ipi *head;
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spinlock_t lock;
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struct smtc_ipi *tail;
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int depth;
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};
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static inline void smtc_ipi_nq(struct smtc_ipi_q *q, struct smtc_ipi *p)
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{
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long flags;
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spin_lock_irqsave(&q->lock, flags);
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if (q->head == NULL)
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q->head = q->tail = p;
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else
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q->tail->flink = p;
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p->flink = NULL;
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q->tail = p;
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q->depth++;
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#ifdef SMTC_IPI_DEBUG
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p->sender = read_c0_tcbind();
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p->stamp = read_c0_count();
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#endif /* SMTC_IPI_DEBUG */
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spin_unlock_irqrestore(&q->lock, flags);
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}
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static inline struct smtc_ipi *__smtc_ipi_dq(struct smtc_ipi_q *q)
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{
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struct smtc_ipi *p;
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if (q->head == NULL)
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p = NULL;
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else {
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p = q->head;
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q->head = q->head->flink;
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q->depth--;
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/* Arguably unnecessary, but leaves queue cleaner */
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if (q->head == NULL)
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q->tail = NULL;
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}
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return p;
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}
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static inline struct smtc_ipi *smtc_ipi_dq(struct smtc_ipi_q *q)
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{
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unsigned long flags;
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struct smtc_ipi *p;
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spin_lock_irqsave(&q->lock, flags);
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p = __smtc_ipi_dq(q);
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spin_unlock_irqrestore(&q->lock, flags);
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return p;
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}
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static inline void smtc_ipi_req(struct smtc_ipi_q *q, struct smtc_ipi *p)
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{
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long flags;
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spin_lock_irqsave(&q->lock, flags);
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if (q->head == NULL) {
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q->head = q->tail = p;
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p->flink = NULL;
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} else {
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p->flink = q->head;
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q->head = p;
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}
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q->depth++;
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spin_unlock_irqrestore(&q->lock, flags);
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}
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static inline int smtc_ipi_qdepth(struct smtc_ipi_q *q)
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{
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long flags;
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int retval;
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spin_lock_irqsave(&q->lock, flags);
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retval = q->depth;
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spin_unlock_irqrestore(&q->lock, flags);
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return retval;
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}
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extern void smtc_send_ipi(int cpu, int type, unsigned int action);
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#endif /* __ASM_SMTC_IPI_H */
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